A first major test of how a candidate might govern: choosing a running mate.

Rick Scott flunked that one.

On Tuesday, just seven days into Scott’s third regular legislative session, Lt. Gov. Jennifer Carroll resigned amid a racketeering investigation of Allied Veterans of the World, an Internet gambling operation that masqueraded as a charity .

“I have no knowledge that she broke the law,” Scott told reporters the next day.

For a candidate who campaigned to clean up Tallahassee and fight special interests, that’s a tough line to deliver.

Now he gets a do-over pick, a campaign-trail make-up exam.

Republican advisers would love a Hispanic female — two coveted demographics — preferably one involved in education. Two names from Miami, state Sen. Anitere Flores and Miami-Dade School Board Member Raquel Regalado, fit the bill. So do others.

But regardless of whom Scott chooses, the Carroll bombshell does nothing to help the governor and his flatlined poll numbers heading into his 2014 reelection campaign.

Unlike some of Scott’s other mistakes, this was probably less an unforced error than bad luck.

Still, it’s another reminder of how Scott talked tough about ethics only to do little about it when he got into office. The candidate who warned about “Tallahassee insiders” in the 2010 GOP primary turned around and picked one in Carroll, then a Republican House member.

Carroll’s public-relations firm represented Allied Veterans while she served in the Florida House. She even cut an ad for the group in 2010. And Carroll’s office filed legislation, quickly withdrawn, that would have benefited Internet cafes.

“It was withdrawn days later at the urging of party leaders who were concerned Carroll had an obvious conflict of interest,” The Florida Times-Union, Carroll’s hometown paper in Jacksonville, wrote in May 2010, months before Scott picked her.

On Tuesday, the Florida Department of Law Enforcement interviewed Carroll in the criminal case against Allied, which has netted 57 arrests so far and involves the federal and state governments from Florida to Oklahoma. The FDLE said Allied used Internet cafes to net about $300 million in revenue.

Hours after the FDLE interview, Scott’s general counsel and chief of staff spoke privately with Carroll for about 45 minutes. She then signed the 30-word resignation letter that they helped draft for her.

The damage control continues.

Now Scott sounds ready to clearly ban Internet cafes, which Carroll had once tried to legalize as she profited from them through Allied.

Scott also insisted the Republican Party of Florida root out Allied Veterans-affiliated contributions and donate the amounts to charity.

When asked about his vetting process for a new running mate, Scott didn’t answer. He said he would pick a replacement after session ends, May 3.

Scott needs to focus on his priorities during the 60-day lawmaking session. The fact that he doesn’t need a lieutenant governor during this period shows how useless the position can be.

A top priority: education, which has cost Scott dearly. His weak poll numbers have languished ever since his first proposed budget cut about $1 billion from education.

Some predicted rookie mistakes from Scott when the political newcomer and unknown ran in 2010:

“We do not need that seat to be a seat where you’re learning, to be a seat where it’s for personal gain, to be a seat where the residents and the citizens of the state of Florida will be negatively impacted because of the lack of vision.”

Jennifer Carroll said that in August 2010. She was then backing Bill McCollum for the GOP gubernatorial nomination. The next month, after Scott won the Republican primary, he picked her.

Carroll’s positives far outweighed her negatives at the time.

She was a legislator, so she knew far more about the Capitol than the neophyte Scott. As a black woman, she had appeal beyond the white-male base of the GOP. And as a veteran (she served in the Navy), Carroll appealed to Florida’s important military vote.

Telegenic and with a touch of glamour, Carroll has added star power: She’s the mother of Miami Dolphins cornerback Nolan Carroll, perhaps best known for being the victim of a rule-breaking sideline trip from a dirty New York Jets coach during a game.

Scott’s vetting team was impressed with Carroll. But there were some concerns.

“She’s a livewire,” said a Scott insider involved in the process. “She had the potential of saying something dumb.”

That happened months after Scott got into office.

A disgruntled employee gave The Florida Times-Union secret recordings of Carroll and her chief of staff. The former employee, Carletha Cole, was fired only to claim she caught Carroll in a lesbian tryst.

Carroll made the story catch fire by suggesting she couldn’t be a lesbian because she’s so good-looking. Outrage followed. So did an apology.

More recently, the governor’s office became concerned that Carroll was spending too much taxpayer money traveling.

With all that trouble, was Scott going to keep her on the 2014 ticket?

“It doesn’t matter,” Scott said the day after she quit. “She did the right thing for the state and her family.”